1. Field of the Invention
The present invention relates to an illumination system and an illumination control method, and more particularly to a technical field of controlling a light emitting diode dynamically based on the detection of ambient light.
2. Description of the Related Art
Please referring to FIG. 1 for a block diagram of an illumination system in accordance with the prior art, the illumination system comprises a control module 11, an illumination module 12 and a light detection module 13. The illumination module 12 comprises a red light emitting diode 121, a green light emitting diode 122 and a blue light emitting diode 123. The control module 11 comprises a microprocessor 111 and three driving modules 113, 114, 115. The driving module 113, 114, 115 generate PWM signals to drive a red light emitting diode 121, a green light emitting diode 122 and a blue light emitting diode 123 to emit lights respectively. The light detection module 13 comprises a red light sensor 131, a green light sensor 132 and a blue light sensor 133, for detecting the intensity of lights produced by the red light emitting diode 121, the green light emitting diode 122 and the blue light emitting diode 123 respectively. The microprocessor 111 compares the detection results of these optical sensors with a predetermined spectral distribution 112 and controls the driving module 113, 114, 115 to adjust the intensity of lights produced by the light emitting diodes 121, 122, 123 based on the comparison results respectively. For example, the microprocessor 11 can control the length or proportion of a duty cycle of a PWM signal generated by the driving module to change the illumination intensity of the light emitting diodes.
With the foregoing technical content, the illumination system in accordance with the prior art can emit a light matching with the predetermined spectral distribution 112. Even if some of the light emitting diodes have a drop of illumination intensity caused by a temperature factor or aged material, the microprocessor 11 still can adjust the PWM signal to improve the illumination intensity of these light emitting diodes, and further maintain the light produced by the illumination module 12 to match with the predetermined spectral distribution 112. For instance, if the illumination system is applied to an LCD screen, the light on the screen is maintained as white light to provide comfortable viewing for users. However, if the color temperature of the ambient light is changed, for example a bulb having higher color temperature is used in a room, and emits a slightly red light, so that the screen will show a slightly red phenomenon even if the foregoing illumination system is used. If a bulb having a lower color temperature is used in a room, and emits a slightly blue light, and the screen will show a slightly blue phenomenon, and thus the colors of an image cannot be displayed correctly.
In view of the drawbacks of the prior art, the inventor of the present invention based on years of experience in the related field to propose an illumination method and an illumination control method to overcome the foregoing drawbacks of the prior art.